In various types of circuits, interference can cause problems with the operation of the circuits. These types of problems may be especially evident in highly integrated systems, where the operation of one portion of a device can interfere with the operation another portion of the device. For example, in a circuit containing both RF circuitry and digital circuitry, interference between the RF and digital circuitry can cause significant disturbance to the RF circuits, making the implementation on an integrated circuit very difficult.
In a typical prior art RF receiver, transmitter, or transceiver, RF circuitry generally resides in a different circuit partition (e.g., integrated circuit (IC), die, etc.) than does signal-processing circuitry (e.g., baseband), partly due to the problem of interference. RF circuitry typically includes analog circuitry that has a relatively high sensitivity to noise and interference. Furthermore, the RF circuitry in some applications, for example, in a mobile telephone apparatus, may have to detect signals as small as a few nano-volts in amplitude. The performance of a device may suffer as a result of noise and interference from sources external or even internal to the communication apparatus.
In a typical communication apparatus, such as a mobile telephone apparatus, digital circuitry produces digital signals with relatively small rise and fall times, or with fast transitions or sharp edges. Furthermore, those signals often have relatively high frequencies. As a result, these high frequency signals, and their harmonics, can interfere with, and adversely impact the performance of, the RF circuitry. As a result, typical prior art communication devices use more than one circuit partition. For example, one partition may include the RF circuitry, while a second partition includes the digital circuitry.
Using more than one partition for RF circuitry and the digital circuitry, however, has several disadvantages, such as increased component count, size, and overall cost, and more potential for decreased reliability and increased manufacturing failures. Therefore, a need exists for highly integrated devices having all circuitry in one partition. For example, in the field of RF communication devices, there is a need for a highly integrated RF apparatus that includes a complete radio in one partition, die, IC, etc.